Tuned performance sport tube

ABSTRACT

A tuned high performance sporting device comprising stiffened portions and flexible portions is taught. The invention is particularly well suited to ball bats. One embodiment of the ball bat includes a hollow tube having an impact portion, a handle portion and a tapered mid-section connecting the two. A core having a substantially hollow interior and an outer diameter, preferably at least as large as the impact portion inner diameter is located in the impact portion of the ball bat. A fill material is located in the core interior to connect the core to the interior of the impact portion. Methods of manufacturing and utilizing these tuned devices are also disclosed.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to high performance sporting devices, in particular it relates to ball bats. In an effort to continually improve bats, manufacturers seek out new materials and designs. Most top end bats utilize the highest tensile and yield strengths available, such as the 7000 series hard alloys, titanium, and composites, all of which are available to manufacturers. Therefore, in an effort to differentiate products based on performance utilizing the same materials, manufacturers and engineers usually seek out new designs to enhance performance and durability.

[0002] One such design is U.S. Pat. No. 5,364,095, assigned to Easton, et al. In this patent the inventors attempt to improve the durability and performance of the bat by reinforcing the interior walls with a composite material.

[0003] Another such design is U.S. Pat. No. 5,511,777 by McNeely. The invention provides a damped core ball bat including an inner damper that is covered by a resilient attenuator sleeve. The inner damper is inserted into the hollow tube such that the resilient attenuator sleeve is compressed between the inner damper and the tube wall. The resilient attenuator sleeve is often compressed so that its volume has been reduced 50 to 70% of the original, relaxed state, volume. McNeely utilizes a thinner wall in the barrel portion of the bat. Deformation in the barrel portion wall caused by impact with a ball is transferred to the resilient attenuator sleeve immediately thereunder. Because the resilient attenuator sleeve is very tough and has very high spring back, the kinetic energy from the impact of the ball is recovered and then returned to the ball, giving the bat great rebound. (According to Pat. '777.) In the preferred embodiment of Pat. '777, the attenuator sleeve is made from polystyrene closed cell foam. Preferably the inner damper is made into a hollow tube formed from brass, aluminum, or a like malleable yet lightweight material. Vacant space inside the bat may optionally be filled with foam or sponge, as in conventional bats. Preferably the wall barrel in a preferred embodiment ranges from between 0.07 to 0.08 inches.

[0004] Another design is shown in U.S. Pat. No. 5,415,398 to Eggiman. Eggiman teaches a tubular bat frame elastically deflectable across a gap to engage an insert in the gap. Eggiman requires that a suspended insert contact the tubular frame only at interference fits. A narrow uniform gap exists between the insert and the inner wall of the impact portion. The gap extends uniformly around the insert and along the length of the insert between the first and second ends thereof. Eggiman uses the deflection across the gap impacting the insert to enhance the trampoline effect, and thereby enhance ball rebound.

[0005] U.S. Pat. No. 3,963,239 by Fuji utilizes an insert in the barrel end of a hollow bat to stiffen the hollow bat. FIGS. 1 and 2 of the present disclosure show prior art cores disclosed in Fuji. FIG. 1 shows the prior art bat 2 stiffened with an internal core 4. FIG. 2 shows another embodiment of the core 4 which is formed from a coiled helical strip 6.

SUMMARY OF THE INVENTION

[0006] The present invention relates to high performance sporting equipment. One embodiment of the present invention is a tuned performance sport device including an elongated hollow member having a first portion and a second portion wherein the first portion includes an inner diameter.

[0007] A core having an interior and an outer diameter wherein the outer diameter is at least as large as the first portion inner diameter is located in the first portion. The tuned sport device also includes a first material located in the core interior, wherein the first material presses the core against the first portion.

[0008] While the present invention relates to high performance sporting equipment in general, it more particularly relates to high performance baseball and softball bats. In one embodiment a baseball bat includes a hollow tube having an impact portion and a handle portion and a mid-section connecting the two. The impact portion has a first inner diameter and the handle portion has a second inner diameter. A core having an interior and an uncompressed outer diameter at least as large as the impact portion first inner diameter is located in the impact portion. A fill material is located in a portion of the core interior. The fill material acts to connect at least a portion of the core to the impact portion. Performance characteristics of the ball bat may be adjusted by selecting core and fill material properties and locating a plurality of fill materials and cores in multiple portions of the ball bat.

[0009] Methods of manufacturing the high performance tuned sporting device and the ball bat are also taught herein. Methods of utilizing the ball bat are taught as well.

[0010] One object of the present invention is to provide a high performance ball bat capable of hitting a ball farther than a typical ball bat.

[0011] One object of the present invention is to provide this farther hitting ball bat by utilizing a thin walled hollow tubular bat stiffened in select locations.

[0012] Another object of the present invention is to provide a ball bat having tuned performance characteristics.

[0013] Another object of the present invention is to provide a revolutionary new bat that focuses on total performance for the serious ball player.

[0014] Accordingly an object of the present invention is to provide a bat with superb playing characteristics and durability.

[0015] A further object of the present invention is to provide a bat with improved durability characteristics.

[0016] An object of the present invention is to provide a tuned high performance sport device with an internal mechanical reinforcement system that is a systematic design. When the systematic design is incorporated in a ball bat it is capable of concentrating energy in the bat during the bat and ball collision.

[0017] Another object of the invention is to provide a bat that results in more solid hits.

[0018] Another object of the present invention is to provide a tapered bat design that optimizes the bending of the bat to enlarge the sweet spot and increase performance.

[0019] Yet another object of the invention is to provide a new bat that is significantly different from prior art bats and thereby provides a new feel.

[0020] Another object of the present invention is to provide a tuned performance sport device that is easy to manufacture.

[0021] Other objects and advantages will be apparent from the claims and the following description of preferred embodiments with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 shows a prior art bat stiffened with an internal core.

[0023]FIG. 2 shows another embodiment of the core to be used in FIG. 1.

[0024]FIG. 3 shows a sectioned view of a hollow tubular bat cut lengthwise.

[0025]FIG. 3a shows a sectioned view of the hollow tubular bat of FIG. 3 cut along section line A-A. The lengthwise section removed in FIG. 3 has been replaced in FIG. 3a.

[0026]FIG. 3b shows a sectioned view of the hollow tubular bat shown in FIG. 3 cut along section line B-B. The lengthwise section removed in FIG. 3 has been replaced in FIG. 3b.

[0027]FIG. 4 shows a core to be inserted in the impact portion of the bat.

[0028]FIG. 5 shows a section view of the core cut along section line 5-5 shown in FIG. 4.

[0029]FIG. 6 shows a cut away view of the tubular bat with the core located in the impact portion of the bat.

[0030]FIG. 7 shows the hollow tubular bat with one side removed to show a core located in the impact portion of the bat. A fill material is shown connecting a portion of the core to the bat. A second fill material having a higher density than the first fill material is located at the barrel end of the bat.

[0031]FIG. 8 shows a ball bat including a core in the impact portion and a first fill material disposed substantially throughout the core and the interior of the bat. A second and third fill material are located at the barrel end and handle end respectively. The view in FIG. 8 is a lengthwise cutaway sectioned view.

[0032]FIG. 9 shows simplified center line deformations of a typical ball bat and a thin walled ball bat due to impact by a ball.

[0033]FIG. 10 shows a cut away broken view of a high performance tuned ski pole.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] The present invention relates to high performance sporting equipment. In particular, the present invention relates to high performance baseball and softball bats and methods of manufacturing and utilizing the same. The invention will be best understood when considered in light of the following descriptions; as illustrated in the attached drawings wherein like reference numerals and characters refer to like parts.

[0035] One embodiment of the present invention is for a ball bat 10 as shown in FIG. 7. The ball bat 10 includes a hollow tube 12 having an impact portion 14. The impact portion 14 may be all of or a part of a barrel portion 16. The hollow tube 12 also includes a handle portion 18 and a mid-section 20 there between. The impact portion 14 has a first inner diameter 22. This is shown in FIG. 3a, which is a sectioned view of the impact portion 14 shown in FIG. 3 cut along section line 5-5, the removed lengthwise section has been replace in FIG. 3a. The handle portion 18 has a second inner diameter 24. This is best shown in FIG. 3b, which is a section view of the handle 18 shown in FIG. 3 cut along the section line B-B, the removed lengthwise section has been replace in FIG. 3b.

[0036] The ball bat 10 also includes a core 26. FIG. 4 shows one embodiment of the core 26. FIG. 5 shows a section view of the core shown in FIG. 4 cut along section line 5-5. As best shown in FIG. 5, the core 26 has an interior 28 and a neutral outer diameter 30. The neutral outer diameter 30 is also referred to as an uncompressed, a relaxed, or an at rest, outer diameter. Preferably the core neutral outer diameter 30 is at least as large as the barrel, or impact portion, first inner diameter 22. The core 26 is then located in the impact portion 14. This is shown in FIG. 7. In other embodiments the neutral outer diameter 30 is larger than the first inner diameter 22 of the impact portion 14 when at rest. Preferably, it is compressible with minimal effort and inserted with minimal effort into the impact portion 14. When the core 26 is received in the barrel portion 16 there is zero clearance between the outer diameter of the core 26 and the inner diameter 30 of the barrel 16.

[0037] The ball bat 10 also includes a first fill material 32. As shown in FIG. 7, the first fill material is located in a portion of the core interior 28. The first fill material acts to press at least a portion of the core 26 against the impact portion 14. Preferably, the core exterior is flush with the impact portion interior, allowing for defects of course.

[0038]FIG. 8 shows a section view of a ball bat 10 which is sliced lengthwise through the ball bat 10. The first fill material 32 is disposed substantially throughout the core 26. A second fill material 34 is disposed in a barrel end 36 of the ball bat 10. The barrel end 36 is also referred to as a first end of the hollow tube 12. It is located opposite the handle 18.

[0039] In the embodiment shown in FIG. 8, the second fill material 34 has a higher density than the first fill material 32. This is indicated by the concentration and size of the generally circular markings.

[0040] The core 26 shown in FIG. 8 is a coiled helical element. It is formed from a thin elongated strip 38 which is coiled into a helical spring 41. Individual coils 39 are separated by interstitial spacings 40. The coil 26 shown in FIG. 4 depicts the coils 39 flush with each other. One method of manufacturing the coiled helical element is to laser cut the core 26.

[0041] A third fill material 42 is depicted in the handle 18 shown in FIG. 8. Thus, a plurality of fill materials may be disposed in a variety of sections throughout the interior of the hollow tube 12. The number of fills, quantity of fills, types of fills, and locations at which to place fills will vary with the applications envisioned. This allows for selectively stiffening selective portions of the ball bat. It also provides a means to adjust the weight of selective portions. The core can have a variety of weights and stiffnesses, depending on the material and configuration used to form the core. Separately, or combined, the core and the fill materials can be used to adjust a variety of performance characteristics, including weight, stiffness (i.e. bending and flexure), and frequency response (including damping), and thereby tune the bat.

[0042] In one embodiment of the present invention the ball bat 10 includes the first fill material 32 in the mid-section 20. This is shown in FIG. 7. In another embodiment the handle portion 18 includes the first fill material 32. In one embodiment the ball bat 10 comprises the second fill material 34 and the first fill material 32 in the core interior 28. This is shown in both FIGS. 7 and 8.

[0043] In one embodiment the first fill material comprises a polyurethane foam. An example of one such polyurethane foam may be IE 90-A polyurethane elastomer provided by Innovative Polymers, Inc. located at 208 Kuntz Street, St. Johns, Mich. 48879. The IE 90-A is a tough, impact resistant polyurethane elastomer formulated for room temperature hand batch processing. Excellent physical properties are obtained with room temperature cure without the utilization of MOCA or TBI. Typical properties for the polyurethane elastomer are given below. Typical Properties of IE 90-A Resin/Hardener ratio (Pts. By Weight) 38/100 Resin/Hardener ratio (Pts. By Volume) 33/100 Resin viscosity (@ 77° F.) 100 cps Hardener viscosity (@ 77° F.) 1500 cps Initial mixed viscosity 975 cps Working life 20 mins. Demold time (@ 77° F.) Approx. 8 hrs.

[0044] In one embodiment the first fill material 32 is less dense than the second fill material 34. One material suitable for a second fill material 34 is ELASTOFLEX 25491R Resin/WUC 3192T Isocyanate provided by BASF Corportation Chemical Division located at 1609 Biddle Avenue, Wyandotte, Mich. 48192. ELASTOFLEX 25491R Resin/WUC 3192T Isocyanate is a two component semi-rigid fill. Typical properties of this material follow. EXEMPLARY FILL MATERIAL PROPERTIES Category Mixture Ratios @ 110 index 100 parts of ELASTOFLEX 25491R Resin/ 60.6 parts of WUC 3192T Isocyanate @ 115 index 100 parts of ELASTOFLEX 25491R Resin/ 63.4 parts of WUC 3192T Isocyanate @ 120 index 100 parts of ELASTOFLEX 25491R Resin/ 66.2 parts of WUC 3192T Isocyanate

[0045] EXEMPLARY FILL MATERIAL CHARACTERISTICS Cream TOC String Gel Rise Tack Density 14 sec 32 sec 34 sec 48 sec 51 sec 31.1 pcf

[0046] One embodiment of the ball bat 10 includes the first fill material 32 being a low density polyurethane foam and the second fill material 34 being a high density polyurethane foam, wherein the high density polyurethane foam is high relative to the low density polyurethane foam. Thus, the invention is not limited to the specific materials discussed above.

[0047] As mentioned previously, the core 26 may be adapted to be inserted into the impact portion 14 with minimal effort. One method of adapting the core includes forming the core 26 into a coiled helical element. The coiled helical element typically includes a thin elongated strip 38 coiled into a helical spring 41. Other hollow, or semi hollow, core designs will be apparent from the teachings herein to obtain the objects taught herein. This is shown in FIG. 8. In one embodiment, the hollow tube 12 is formed from a first metallic material and the core 26 is formed from a second metallic material.

[0048] Preferably, the first metallic material is thin walled aluminum where thin is measured relative to a typical ball bat aluminum thickness. A series 7000 alloy is an example of a preferred aluminum material. Preferably the wall thickness 42 of the hollow tube 12 shown in FIG. 3A, is between 0.065 inches and 0.080 inches. In another embodiment, the preferred wall thickness 42 range is 0.045 inches to 0.060 inches.

[0049] A ball bat formed from a thin walled tube has greater flexure than a typical hollow bat formed from the same material. Thus, the entire bat, in particular, the tapered mid-section would bend more than a typical hollow bat of the same material when impacted by a ball in similar locations.

[0050]FIG. 9 illustrates this concept. FIG. 9 shows a ball bat 50 including a centerline 52. A deformed centerline 54 corresponds to a simplified deformation of a typical hollow ball bat. Deformed centerline 56 corresponds to a simplified deformation, (bending, or flexure) achieved with a thin walled hollow ball bat.

[0051] It can also be shown that as the wall thickness decreases in the most common bats, the amount of transferred energy increases. However, the amount of energy transferred due to changes in wall thickness does not account for the differences in total response of the bats due to changes in wall thickness. The natural frequency of the bat is another component that effects the performance characteristics of the bat. As the wall thickness increases, the natural frequency increases.

[0052] Thus, the dynamic response of the bat due to a given impact can be tuned to provide a given response by selecting particular wall thicknesses. The bat can be further tuned using cores and fills as discussed above.

[0053] A thin walled bat, however, may be susceptible to durability limitations. This is particularly true in the impact region, which receives the greatest abuse. Accordingly one object of the present invention is to provide a stiffened impact portion for a thin walled ball bat. In keeping with this, in one embodiment of the present invention the first fill material 32 is polyurethane foam and the neutral outer diameter 30 of the core 26, preferably a coiled helical element, is greater than the first inner diameter 22 of the impact portion 14. The polyurethane foam is located in the helical element interior 28. Together the core and the fill, located in the impact portion 14 of the hollow tube 12, form a stiffened impact portion 58. Preferably the stiffened impact portion 58 has a stiffness as large as the stiffness of a typical comparable ball bat e.g. a bat having typical wall thicknesses. This would increase the durability of the impact portion while maintaining the greater flexibility in the mid-section 20 of the thin wall ball bat 10.

[0054] In one embodiment the ball bat 10 of the present invention further includes the impact portion 14 comprising a first outer diameter 60 (see FIG. 3a) and the handle portion 18 comprising a second outer diameter 62 (see FIG. 3b), wherein the second outer diameter 62 of the handle 18 is smaller than the first outer diameter 60 of the impact portion 14. Preferably the mid-section 20 comprises a thin wall having a thickness less than a typical hollow bat. The mid-section 20 is generally manufactured through a swaging process and tapered from the first outer diameter 60 of the impact portion 14 down to the second outer diameter 62 of handle portion 18.

[0055]FIG. 8 shows the first fill material 32 disposed substantially throughout the hollow tube 12. In one embodiment the first fill material 32 comprises a density indicated in FIG. 8 by larger and more widely spaced circular markings than the other fill materials in FIG. 8. The hollow tube 12 further comprises an impact portion end, also referred to as a barrel end 36. An end plug 64 is located in the impact end 36.

[0056] This is shown in FIG. 3. A second fill material 34 is located in the hollow tube 12 near the end plug 64. This is shown in FIG. 8. Preferably the second fill material 34 has a density which is greater than the first fill density.

[0057] One embodiment of the present invention includes a ball bat 10 comprising a 20 tube 12 having an interior 66, a barrel portion 16 including an outer diameter 60 and an inner diameter 22. See FIG. 6 and FIG. 3a. The tube 12 also includes a handle portion 18 having an outer diameter 62 and an inner diameter 24, wherein the outer diameter 62 is smaller than the barrel portion outer diameter 60. The tube 12 also includes a tapered section 20 connecting the barrel portion 16 to the handle portion 18. A core 26 having an uncompressed outer diameter 30 at least as large as the barrel portion 16 inner diameter 22 is located in the barrel portion 16 of the ball bat 10. See FIGS. 5 and 6. A first fill material 32 is located in the core 26. The first fill material 32 is not shown in FIG. 6 for clarity. Typically the barrel portion 16 of the ball bat 10 includes an impact portion 14, and the core 26 includes a portion bonded to the impact portion by the first fill material 32. See FIG. 7. In one embodiment, the first fill material 32 expands upon curing, applying an outward force against the core interior 28, which in turn compresses the core against the tube 12 interior 66.

[0058] In some embodiments of the ball bat 10, the barrel portion 16 has an impact portion 14 and the core 26 positioned in the impact portion 14 is a coiled helical spring. The first fill material 32 generally connects the coiled helical spring 41 to the impact portion 14. The barrel portion 16 may further include a barrel end 36 opposite the handle portion 18 wherein a second fill material 34 is disposed in the barrel end 36.

[0059]FIG. 8 depicts a ball bat 10 in which the first fill material 32 is a low density material disposed substantially throughout the tube interior 66. The ball bat 10 shown in FIG. 8 includes a second fill material 34 which is a high density material relative to the low density material of the first fill material 32.

[0060] Preferably the tube 12 comprises a wall thickness 42 less than a wall thickness of a typical hollow ball bat. In a preferred embodiment the tube is a thin walled aluminum shell having a wall thickness less than 0.10 inches. In one preferred embodiment the wall thickness 42 is substantially uniform.

[0061] The following table compares preferred the wall thickness 42 of bats manufactured according to the present invention with typical wall thicknesses of comparable bats. WALL THICKNESS COMPARISON Typical Usage Bats of Present Invention Typical Bats Softball 0.055″ 0.070-0.085″ Baseball 0.075″ 0.110-0.130″ Baseball 0.070-0.075″ 0.110-0.125″

[0062] The present invention also includes a method of manufacturing a ball bat 10 comprising the steps of providing a tube 12 having a barrel portion 16 including an inner diameter 22 and a handle portion 18, and inserting a core 26 having an interior 28 into the barrel portion 16, wherein the core 26 has an uncompressed outer diameter 30 at least as large as the barrel portion inner diameter 22. The method further includes inserting a first fill material 32 into the core interior 28.

[0063] One embodiment of the method includes utilizing a foam as the fill material; allowing the foam to expand; and maintaining the core 26 against an interior 68 of the barrel 16 with the expanded foam. The method may further include inserting a second fill material 34 into the core interior 28.

[0064] The method of manufacturing the ball bat 10 may further include the steps of providing a plurality of fill materials including a first fill material 32, wherein the plurality of materials have a plurality of respective densities and inserting the plurality of fill materials, including the first fill material, into a plurality of respective tube portions. See FIGS. 7 and 8. The method may further comprise the step of adjusting a plurality of performance characteristics of the ball bat 10 by placing a respective fill material at a respective tube portion and by selecting the respective fill density for the respective tube portions to achieve a given performance. This allows the hollow tube 12 to be selectively stiffened at selective portions. The method may further comprise inserting an end plug 64 into the barrel portion 16, and filling an end portion 36 of the barrel portion with a second material 34.

[0065] One method of manufacturing the ball bat 10 comprises the steps of forming the core 26 into a coiled helical spring 41 and locating the coiled helical spring 41 in an interior 68 of an impact portion 14 of the barrel portion 16. Generally the method includes bonding a portion of the coiled helical spring 41 to the interior 68 of the impact portion 14 with the first fill material 32. This is shown in FIG. 7.

[0066] Generally the step of providing a tube comprises providing a thin walled tube having greater flexure than a comparable tube having a typical wall thickness of a typical ball bat. Accordingly, the method may further include the steps of allowing the ball bat to bend more upon being struck by a ball than a typical ball bat bends upon being struck by a ball, and achieving and maintaining a typical ball bat stiffness in the impact portion located in the barrel portion.

[0067] Consequently a method of the present invention includes a method of hitting a ball further with an improved ball bat than with a typical ball bat. The method of hitting may include the steps of providing a flexible ball bat 10 having a greater flexure than the typical ball bat, and stiffening an impact portion 14 of the flexible ball bat 10, wherein the step of stiffening includes inserting a core 26 that has an uncompressed outer diameter 30 at least as large as an inner diameter 22 of the impact portion 14 into the impact portion 14.

[0068] The method of hitting further includes inserting a fill material 32 into the core 26, maintaining contact between the core 26 and the impact portion 14 and allowing the flexible ball bat 10 to have greater flexure than a typical ball bat has under like conditions while stiffening the impact portion 14.

[0069] The method of hitting a ball includes impacting a ball in the impact portion, whereby the flexible ball bat 10 flexes more than a standard ball bat at a plurality of locations other than the stiffened impact section. A rebounding spring force produced at the plurality of locations imparts a greater force to the ball than would a typical ball bat having a respective plurality of locations which are stiffer than the plurality of locations on the flexible ball bat.

[0070] Another embodiment of the present invention includes a tuned performance support device 70. FIG. 10 shows a partial and broken sectioned view of a high performance tuned sporting device in the form of a ski pole.

[0071] Examples of other tuned performance sporting devices are golf clubs, bicycle seat posts, bicycle forks and other frame members, rackets for racket sports, and the like. The tuned performance sport device 70 includes an elongated hollow member 72 having a first portion 74 and a second portion 76 wherein the first portion includes an inner diameter 78. The tuned sport device also includes a core 80 having an interior 82 and an outer diameter 84, wherein the outer diameter 84 is at least as large as the first portion inner diameter 78. The tuned sport device 80 also includes a first fill material 90 located in the core interior 82, wherein the first fill material 90 presses the core 80 against the first portion 74.

[0072] In the embodiment shown in FIG. 10 the first portion 74 of the hollow member 72 has a circular cross-section and the core has a circular cross-section. Variations of cross sections for specific applications will be apparent to those with skill in the art.

[0073] A method of manufacturing a tuned performance sport device 80 may comprise the steps of: (1) providing an elongated hollow member 72 having a first portion 74 and a second portion 76; (2) stiffening the first portion to a predetermined stiffness; (3) inserting a core having an uncompressed outer diameter at least as large as an inner diameter of a first portion into the first portion; and (4) inserting a first fill material 90 at an interior of the core. The method of manufacturing may further comprise the steps of adjusting performance characteristics of the tuned performance sport device.

[0074] One embodiment of the manufacturing method includes utilizing a first fill material having a first density; and adjusting performance characteristics by selecting the first fill material 90, at least in part based upon the first density of the first fill material 90. The step of adjusting performance characteristics may further comprise the steps of selecting a second fill material 92 having a second density; and locating the first and second fill materials 90 and 92 at a plurality of locations in the hollow member 72, including locating the first fill material 90 in the core interior 82. The second fill material 92 may also be located in a portion of the core interior.

[0075] Thus, although there have been described particular embodiments of the present invention of a new and useful Tuned Performance Sport Tube, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims. 

What is claimed is:
 1. A ball bat comprising: a hollow tube having an impact portion, a handle portion, and a mid-section there between, wherein the impact portion has a first inner diameter and the handle has a second inner diameter; a core having an interior and a neutral outer diameter at least as large as the first inner diameter, the core located in the impact portion; and a first fill material in the core interior pressing the core against the impact portion.
 2. The ball bat of claim 1 wherein the mid-section includes the first fill material.
 3. The ball bat of claim 2 wherein the handle portion includes the first fill material.
 4. The ball bat of claim 1 wherein the first fill material comprises a polyurethane foam.
 5. The ball bat of claim 1 , further comprising a second fill material in the core interior.
 6. The ball bat of claim 2 wherein the hollow tube further comprises: a first end opposite the handle, wherein the impact portion is interposed the first end and the handle portion; and wherein the first end includes a second fill material.
 7. The ball bat of claim 6 wherein the first fill material is less dense than the second fill material.
 8. The ball bat of claim 6 wherein: the first fill material comprises a low density polyurethane foam; and the second fill material comprises a high density polyurethane foam, and wherein the high density polyurethane foam is high relative to the low density polyurethane foam.
 9. The ball bat of claim 1 wherein the core is adapted to be inserted into the impact portion with minimal effort.
 10. The ball bat of claim 9 wherein the core is a coiled helical element.
 11. The ball bat of claim 10 wherein the coiled helical element comprises a thin elongated strip coiled into a helical spring.
 12. The ball bat of claim 10 wherein: the hollow tube is formed from a first metallic material; and the core is formed from a second metallic material.
 13. The ball bat of claim 10 wherein the first fill material is polyurethane foam, the neutral outer diameter of the coiled helical element is greater than the first inner diameter of the impact portion, and wherein the polyurethane foam in the helical element interior, together with the impact portion of the hollow tube form a stiffened impact portion having a stiffness at least as large as a stiffness of a typical comparable ball bat.
 14. The ball bat of claim 1 wherein: the impact portion comprises a first outer diameter; the handle portion comprises a second outer diameter, wherein the second outer diameter is smaller than the first outer diameter; and the mid-section comprises a thin wall having a thickness less than a typical hollow ball bat, and wherein the mid-section is tapered from the first outer diameter to the second outer diameter.
 15. The ball bat of claim 1 wherein the hollow tube further comprises a thin wall having a thickness less than a typical hollow bat.
 16. The ball bat of claim 15 wherein the core is a coiled helical spring.
 17. The ball bat of claim 15 wherein the first fill material is disposed substantially throughout the hollow tube.
 18. The ball bat of claim 17 wherein: the first fill material comprises a density; and the hollow tube further comprises an impact portion end opposite the handle portion, an end plug in the impact portion end, and a second fill material located in the hollow tube near the end plug, wherein the second fill material has a density higher than the first fill material density.
 19. The ball bat of claim 16 wherein the coiled helical element includes at least a portion bonded to the impact portion by the first fill material.
 20. A ball bat comprising: a tube having an interior, a barrel portion including an outer diameter and an inner diameter, a handle portion including an outer diameter smaller than the barrel portion outer diameter, and a tapered section connecting the barrel portion and the handle portion; a core having an uncompressed outer diameter at least as large as the barrel portion inner diameter, the core being located in the barrel portion; and a first fill material in the core.
 21. The ball bat of claim 20 , wherein the barrel portion includes an impact portion and the core includes a portion bonded to the impact portion by the first fill material.
 22. The ball bat of claim 20 , further comprising a second fill material in the core.
 23. The ball bat of claim 20 , wherein: the barrel portion includes an impact portion; wherein the core is a coiled helical spring positioned in the impact portion; and wherein the first fill material connects the coiled helical spring to the impact portion.
 24. The ball bat of claim 23 , wherein the barrel portion includes a barrel end opposite the handle portion, and wherein a second fill material is disposed in the barrel end.
 25. The ball bat of claim 24 , wherein the first fill material is a low density material disposed substantially throughout the tube interior and the second fill material is a high density material relative to the low density material.
 26. The ball bat of claim 24 , wherein the barrel end includes an end plug.
 27. The ball bat of claim 23 , wherein the tube comprises a wall thickness less than a wall thickness of a typical hollow ball bat.
 28. The ball bat of claim 23 , wherein the tube is a thin-walled aluminum shell having a wall thickness less than 0.10 inches.
 29. The ball bat of claim 28 , wherein the wall thickness of the thin-walled aluminum shell is substantially uniform.
 30. A method of manufacturing a ball bat comprising the steps of: providing a tube having a barrel portion, including an inner diameter and a handle portion; inserting a core having an interior into the barrel portion wherein the core has an uncompressed outer diameter at least as large as the barrel portion inner diameter; and inserting a first fill material into the core interior.
 31. The method of claim 30 , comprising the steps of: utilizing a foam as the fill material; allowing the foam to expand; and maintaining the core against an interior of the barrel with the expanded foam.
 32. The method of claim 30 , comprising the step of inserting a second fill material into the core interior.
 33. The method of claim 30 , comprising the steps of: providing a plurality of fill materials, including the first fill material, wherein the plurality of fill materials has a plurality of respective densities; and inserting the plurality of fill materials, including the first fill material, into a plurality of respective tube portions.
 34. The method of claim 33 , further comprising the step of adjusting a plurality of performance characteristics of the ball bat by placing a respective fill material at a respective tube portion by selecting a respective density for the respective fill material.
 35. The method of claim 30 further comprising the steps of: inserting an end plug into the barrel portion; and filling an end portion of the barrel portion with a second fill material.
 36. The method of claim 32 , further comprising the steps of: forming the core into a coiled helical spring; locating the coiled helical spring in an interior of an impact portion of the barrel portion; and bonding a portion of the coiled helical spring to the interior of the impact portion with the first fill material.
 37. The method of claim 30 , wherein the providing a tube step comprises providing a thin-walled tube having greater flexure than a comparable tube having a typical wall thickness for a typical ball bat.
 38. The method of claim 37 , further comprising the step of adjusting a plurality of performance characteristics of the ball bat.
 39. The method of claim 38 , further comprising the steps of: allowing the ball bat to bend more upon being struck by a ball than a typical ball bat bends upon being struck by a ball; and achieving and maintaining a typical ball bat stiffness in an impact portion located in the barrel portion.
 40. A method of hitting a ball further with an improved ball bat than with a typical ball bat, the method comprising the steps of: providing a flexible ball bat having greater flexure than the typical ball bat; stiffening an impact portion of the ball bat, wherein the step of stiffening includes inserting a core having an uncompressed outer diameter at least as large as an inner diameter of the impact portion into the impact portion; inserting a fill material into the core; maintaining contact between the core and the impact portion; allowing the flexible ball bat to have greater flexure than a typical ball bat has under like conditions while stiffening the impact portion; and impacting a ball in the impact portion, whereby the flexible ball bat flexes more than a standard ball bat at a plurality of locations other than the stiffened impact section and whereby a rebounding spring force from the plurality of locations imparts a greater force to the ball than would a typical ball bat wherein a respective plurality of locations on the typical ball bat are stiffer than the plurality of locations on the flexible ball bat.
 41. A tuned performance sport device comprising: an elongated hollow member having a first portion and a second portion, wherein the first portion includes an inner diameter; a core having an interior and an outer diameter, wherein the outer diameter is at least as large as the first portion inner diameter; and a first fill material located in the core interior, wherein the first fill material compresses the core against the first portion.
 42. The device of claim 41 , wherein the first portion of the hollow member has a circular cross section, and the core has a circular cross section.
 43. A method of manufacturing a tuned performance sport device comprising the steps of: providing an elongated hollow member having a first portion and a second portion; stiffening the first portion to a predetermined stiffness; inserting a core having an uncompressed outer diameter at least as large as an inner diameter of the first portion into the first portion; inserting a first fill material in an interior of the core.
 44. The method of claim 43 , further comprising the step of adjusting performance characteristics of the tuned performance sport device.
 45. The method of claim 44 , wherein: the first fill material includes a first density; and the step of adjusting performance characteristics comprises selecting the first fill material based upon the first density.
 46. The method of claim 45 , wherein the step of adjusting performance characteristics further comprises the steps of: selecting a second fill material having a second density; and locating the first and second fill at a plurality of locations in the hollow member, including locating the first fill material in the interior of the core.
 47. The method of claim 46 , wherein the locating step comprises the step of locating the second fill material in a portion of the core interior. 